Herbie - Open channel flow...

[SJMFW]

So I've recently converted my durso to a herbie overflow. Super quiet, which makes my wife happy. My question is regarding the flow of the open channel. I've attached a video, can anyone tell me if this is more than the recommended "trickle"?

 

[FSP]

Folks have two thoughts on this. I don't think there should be any for safety, but if you're using it as an open channel, any amount that's quiet is fine. If it's noisy, open the siphon more.

 

[SJMFW]

@FSP Thanks for the response, could you elaborate on your safety concern?

 

[WVNed]

There are 2 concerns.

If it takes 2 pipes to flow the water to your sump and 1 plugs up the other will not be able to handle the flow.
This discounts the valve on the full siphon drain being closed some. The open drain should never have a valve on it.
It must be able to be covered by enough water to go full siphon without overflowing the box however if it in an external overflow or the tank if an internal. This only requires about 2 inches. There will be some loud surging involved.

The second is a pipe with slow flow may grow stuff in it. It may always pass the trickle but when you need a large flow it wont happen. Test your emergency drains occasionally. This isn't really a problem if the drains go straight down to a sump. Lot's of people like me have drains that are longer and go sideways.

 

[FSP]

Basically the growth stuff WVNed mentioned and clogging risk. It's a beananimal without a dry emergency.

 

[homer1475]

Run a herbie for many years now. I always run it so there is about an 1/8" of an inch before the water goes over the emergency. Basically a dry emergency. If my filter socks are plugged up, or something crawls down the siphon, the emergency makes a noise I can hear it and can respond to it.

 

[SJMFW]

So is growth still a concern if there's an opaque cover in the overflow box preventing any light from entering?

Also, the emergency drain is not flowing out of necessity, I was under the impression the correct way to set up a herbie was to dial the primary drain back to create a "trickle" in the emergency overflow.

I can certainly increase the flow in the primary to keep the emergency drain dry. And I've tested to ensure the emergency drain can handle the flow of the pumps (a loud and stressful test) and it does.

 

[FSP]

It's a saltwater tank, so stuff will grow in your plumbing with or without light.

Trickle seems to be the trend, but I always understood Herbie as a siphon and a dry emergency.

 

[homer1475]

Mine "trickles" from time to time. Usually just minor fluctuations to the system(waves in the overflow, sock filling up, etc, etc). It is dry for the most part.